1. Field of the Invention
The present invention relates to an observation valve structure, and more particularly to one having an inlet pipe joint. The inlet pipe has an outer threaded section at an inner end thereof, an annular guide groove in the inlet pipe joint, and guide holes at the inner end thereof. The annular guide groove communicates with the guide holes. The inlet pipe joint has a stop trough at the inner end thereof for insertion of an annular gasket which is used to clamp one side of a ball shutter. A plate and a handle are pivotally connected to a holder. The handle has an indication plate and a positioning bead and the plate has a positioning hole and two threaded holes to limit and position the handle and to enhance side water flow.
2. Description of the Prior Art
A conventional observation valve, referring to U.S. Pat. No. 6,196,262, comprises a conical connecting body. The center of the conical connecting body has a pipe opening for insertion of a three-way ball shutter. The conical connecting body further has a plurality of holes in a periphery portion for side water flow. A rotatable disc with a lever is provided on top of the observation valve. The rotatable disc is positioned by means of three positioning bead holes of the rotatable disc and a positioning bead disposed under the rotatable disc to control water flow by the three-way ball shutter in the OFF, TEST, DRAIN position. If the conical connecting body is a resilient body, its structure is not strong enough and deformed easily. If the conical connecting body is a rigid body, its mating tolerance must be least. The three-way ball shuttle is wearing easily and the specific parts are not common to increase the cost. The disc is rotated by the positioning bead hole to aim at the positioning bead, without an indication to show the OFF, TEST, DRAIN position. When the elastic member in the positioning bead is fatigued, it is easily displaced by an external force.